The Parable of the Unjust Judge or the Parable of the Importunate Widow is a parable of Jesus found in the Gospel of Luke, 18:1-9. It concerns a judge "who did not fear God, neither did he care for people." Nevertheless, he eventually agreed to do justice to a poor widow because she was so persistent in demanding justice. The framing material of the parable explains that it demonstrates the need to always pray and never give up.
From Luke 18:1-8 (NIV)
Then Jesus told his disciples a parable to show them that they should always pray and not give up. He said: "In a certain town there was a judge who neither feared God nor cared about men. And there was a widow in that town who kept coming to him with the plea, 'Grant me justice against my adversary.'"
"For some time he refused. But finally he said to himself, 'Even though I don't fear God or care about men, yet because this widow keeps bothering me, I will see that she gets justice, so that she won't eventually wear me out with her coming!'"
And the Lord said, "Listen to what the unjust judge says. And will not God bring about justice for his chosen ones, who cry out to him day and night? Will he keep putting them off? I tell you, he will see that they get justice, and quickly. However, when the Son of Man comes, will he find faith on the earth?'"
The framing material relates to one of Luke's favored themes: prayer.
The Jesus Seminar rates the parable as probably authentic ("pink"). It features the reversal of expectations common in Jesus' parables. The framing material is rated inauthentic ("black"). However scholars such as I. Howard Marshall regard all as authentic.